메뉴 건너뛰기




Volumn 25, Issue 26, 2006, Pages 6162-6165

A five-center rather than a four-center transition state for alkene insertion into the metal-alkyl bond of a cationic binuclea yttrium complex

Author keywords

[No Author keywords available]

Indexed keywords

ADDITION REACTIONS; CHEMICAL BONDS; COMPLEXATION; ETHYLENE; MOLECULAR ORIENTATION; PROBABILITY DENSITY FUNCTION;

EID: 33846376108     PISSN: 02767333     EISSN: None     Source Type: Journal    
DOI: 10.1021/om060702i     Document Type: Article
Times cited : (19)

References (79)
  • 1
    • 0036798179 scopus 로고    scopus 로고
    • For examples of reviews, see: (a) Widenhoefer, K. A. Acc. Chem. Res. 2002, 35, 905-913
    • For examples of reviews, see: (a) Widenhoefer, K. A. Acc. Chem. Res. 2002, 35, 905-913.
  • 14
  • 15
  • 27
    • 10244234385 scopus 로고
    • For examples, see: a
    • For examples, see: (a) Woo, T. K.; Ziegler, T. Organometallics 1994, 13, 2252-2261.
    • (1994) Organometallics , vol.13 , pp. 2252-2261
    • Woo, T.K.1    Ziegler, T.2
  • 55
    • 33846371350 scopus 로고    scopus 로고
    • The structure 1 was obtained by static and dynamic computations based on the X-ray structure of its neutral complex precursor [Me2Si(C 5Me4)(μ-PCy)YCH2SiMe3] 2 and was confirmed to be a true active species for the polymerization of isoprene. See ref 7 for more details
    • 2 and was confirmed to be a true active species for the polymerization of isoprene. See ref 7 for more details.
  • 56
    • 33846337302 scopus 로고    scopus 로고
    • The data for isoprene insertion given here are for 4,3-insertion in the methyl-exo fashion. Isoprene 4,3-insertion in the methyl-enifo fashion also prefers a five-center TS pathway (see Supporting Information for more details). Because the 3,4-polyisoprene has been experimentally obtained in very high regioselectivity, the 1,4-insertion fashion was not considered in this work. An attempt to model the 3,4-insertion process finally led to the 1,4-insertion product, which was therefore not considered further. The coordination in a cis-fashion will not alter the reaction pathway.
    • The data for isoprene insertion given here are for 4,3-insertion in the methyl-exo fashion. Isoprene 4,3-insertion in the methyl-enifo fashion also prefers a five-center TS pathway (see Supporting Information for more details). Because the 3,4-polyisoprene has been experimentally obtained in very high regioselectivity, the 1,4-insertion fashion was not considered in this work. An attempt to model the 3,4-insertion process finally led to the 1,4-insertion product, which was therefore not considered further. The coordination in a cis-fashion will not alter the reaction pathway.
  • 57
    • 33846379755 scopus 로고    scopus 로고
    • The slightly large variation trend in solvation energy may result from the fairly high polarity of the chlorobenzene solvent and the significant geometrical variation of the stationary points
    • The slightly large variation trend in solvation energy may result from the fairly high polarity of the chlorobenzene solvent and the significant geometrical variation of the stationary points.
  • 58
    • 33846393738 scopus 로고    scopus 로고
    • 4 and (P2)Me groups sterically inhibit the access of isoprene to Y2 from either the back-side or front-side.
    • 4 and (P2)Me groups sterically inhibit the access of isoprene to Y2 from either the back-side or front-side.
  • 59
    • 33846336289 scopus 로고    scopus 로고
    • An attempt to locate a transition state to connect 3 and 3' was not successful. The reactants 2 and isoprene could be viewed to be in equilibrium with the π-complexes 3 and 3, Scheme 1
    • An attempt to locate a transition state to connect 3 and 3' was not successful. The reactants 2 and isoprene could be viewed to be in equilibrium with the π-complexes 3 and 3' (Scheme 1).
  • 60
    • 0037861823 scopus 로고    scopus 로고
    • The lower stability (higher energy) of 4 than that of 3 might suggest that 4 is a highly reactive intermediate, which could subsequently undergo an energetically favorable isoprene insertion/ polymerization reaction. Such situations have been observed previously in other systems (e.g., Blok, A. N.; Budzelaar, P. H. M.; Gal, A. W. Organometallics 2003, 22, 2564-2570). However, further calculations on the reactions taking place at 4 are difficult because of the hugeness of the computational resources required for such a large system.
    • The lower stability (higher energy) of 4 than that of 3 might suggest that 4 is a highly reactive intermediate, which could subsequently undergo an energetically favorable isoprene insertion/ polymerization reaction. Such situations have been observed previously in other systems (e.g., Blok, A. N.; Budzelaar, P. H. M.; Gal, A. W. Organometallics 2003, 22, 2564-2570). However, further calculations on the reactions taking place at 4 are difficult because of the hugeness of the computational resources required for such a large system.
  • 61
  • 67
    • 0000949944 scopus 로고    scopus 로고
    • Although the second-order perturbative method MP2 (cf. Head-Gordon, M, Head-Gordon, T. Chem. Phys. Lett. 1994, 220, 122-128) could be more accurate, it is difficult to use this method in the present bimetallic system, because it requires much huger computational resources
    • Although the second-order perturbative method MP2 (cf. Head-Gordon, M.; Head-Gordon, T. Chem. Phys. Lett. 1994, 220, 122-128) could be more accurate, it is difficult to use this method in the present bimetallic system, because it requires much huger computational resources.
  • 74
    • 0344861853 scopus 로고    scopus 로고
    • The CPCM model has been widely used for the investigation of the solvation effect in various metal complex systems. For examples, see: (a) Vallet, V, Wahlgren, U, Grenthe, I. J. Am. Chem. Soc. 2003, 125, 14941-14950
    • The CPCM model has been widely used for the investigation of the solvation effect in various metal complex systems. For examples, see: (a) Vallet, V.; Wahlgren, U.; Grenthe, I. J. Am. Chem. Soc. 2003, 125, 14941-14950.
  • 78
    • 33646032123 scopus 로고    scopus 로고
    • Recent computations for group 4 catalyst
    • (b) Recent computations for group 4 catalyst: Talarico, G.; Budzelaar, P. H. M. J. Am. Chem. Soc. 2006, 128, 4524-4525.
    • (2006) J. Am. Chem. Soc , vol.128 , pp. 4524-4525
    • Talarico, G.1    Budzelaar, P.H.M.2
  • 79
    • 33846364463 scopus 로고    scopus 로고
    • Gaussian, Inc, Wallingford, CT, See Supporting Information for full citation
    • Frisch, M. J.; et al. Gaussian 03, Revision C.01; Gaussian, Inc.: Wallingford, CT, 2004. See Supporting Information for full citation.
    • (2004) Gaussian 03, Revision , Issue.C.01
    • Frisch, M.J.1


* 이 정보는 Elsevier사의 SCOPUS DB에서 KISTI가 분석하여 추출한 것입니다.